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|
use std::iter::Copied;
pub enum IonType {
Null = 0x00,
Bool = 0x01,
IntPos = 0x02,
IntNeg= 0x03,
Float = 0x04,
Decimal = 0x05,
Timestamp = 0x06,
Symbol = 0x07,
String = 0x08,
Clob = 0x09,
Blob = 0x0a,
List = 0x0b,
Sexp = 0x0c,
Struct = 0x0d,
Annotations = 0x0e,
}
#[derive(PartialOrd, PartialEq)]
pub struct IonValue(Vec<u8>);
impl IonValue {
pub fn new_null() -> IonValue {
IonValue(vec![0x0F])
}
pub fn ion_type(&self) -> u8 {
self.0[0] >> 4
}
pub fn len(&self) -> usize {
// TODO: Should this read the type length?
self.0.len()
}
pub fn repr_offset(&self) -> usize {
let mut reader = self.reader();
let tl = reader.next_byte();
let _len = reader.extract_length(tl);
reader.offset()
}
pub fn bytes(&self) -> impl DoubleEndedIterator<Item = u8> + '_ {
self.0.iter().copied()
}
pub fn reader(&self) -> IonReader<impl DoubleEndedIterator<Item = u8> + '_> {
IonReader::new(self.0.iter().copied(), 0)
}
pub fn reader_at(&self, offset: usize) -> IonReader<Copied<std::slice::Iter<'_, u8>>> {
IonReader::new(self.0[offset..].iter().copied(), offset)
}
pub fn struct_reader_at(&self, offset: usize) -> IonReader<Copied<std::slice::Iter<'_, u8>>> {
IonReader::new_struct(self.0[offset..].iter().copied(), offset)
}
pub fn to_usize(&self) -> usize {
self.reader().next_usize()
}
}
impl From<Vec<u8>> for IonValue {
fn from(value: Vec<u8>) -> Self {
if value.len() > 0 {
IonValue(value)
} else {
IonValue(vec![0x0F])
}
}
}
pub struct IonReader<T> {
iter: T,
offset: usize,
is_struct: bool,
field_name: Option<usize>,
}
impl <T> IonReader<T>
where T: Iterator<Item = u8>
{
pub fn new(iter: T, offset: usize) -> IonReader<T> {
IonReader {
iter,
offset,
is_struct: false,
field_name: None,
}
}
pub fn new_struct(iter: T, offset: usize) -> IonReader<T> {
IonReader {
iter,
offset,
is_struct: true,
field_name: None,
}
}
pub fn offset(&self) -> usize {
self.offset
}
pub fn field_id(&self) -> Option<usize> {
self.field_name
}
/// Move the iterator to the first nested value.
pub fn step_in(&mut self) -> (u8, usize) {
self.prepare_next();
let tl = self.next_byte();
let len = self.extract_length(tl);
if (tl & 0xF0) == 0xD0 {
self.is_struct = true;
}
(tl >> 4, self.offset + len)
}
fn prepare_next(&mut self) {
if self.is_struct {
// TODO: symbol length can be greater than max usize.
self.field_name = Some(self.next_varuint());
}
}
pub fn skip_value(&mut self) {
self.prepare_next();
let tl = self.next_byte();
let len = self.extract_length(tl);
for _ in 0..len {
self.next_byte();
}
}
pub fn next_value(&mut self) -> IonValue {
self.prepare_next();
let tl = self.next_byte();
let (mut buf, len) = match tl & 0x0F {
0 | 15 => (vec![tl], 0),
14 => {
let l = self.next_varuint();
let mut v = Vec::with_capacity(5 + l);
v.push(tl);
push_varuint(&mut v, l);
(v, l)
},
len => {
let l = len.into();
let mut v = Vec::with_capacity(5 + l);
v.push(tl);
(v, l)
}
};
for _ in 0..len {
let b = self.next_byte();
buf.push(b);
}
buf.into()
}
pub fn next_usize(&mut self) -> usize {
self.prepare_next();
let tl = self.next_byte();
if tl & 0xF0 != 0x20 {
panic!("Not a positive integer");
}
let len = self.extract_length(tl);
if len * 8 > usize::BITS as usize {
panic!("Integer too large for usize");
}
let mut value = 0;
for _ in 0..len {
let b = self.next_byte();
value <<= 8;
value |= b as usize;
}
value
}
fn next_byte(&mut self) -> u8 {
self.offset += 1;
self.iter.next().expect("Missing data")
}
fn extract_length(&mut self, tl: u8) -> usize {
match tl & 0x0F {
0 | 15 => 0,
14 => self.next_varuint(),
len => len.into(),
}
}
fn next_varuint(&mut self) -> usize {
let mut v: usize = 0;
while let Some(b) = self.iter.next() {
self.offset += 1;
v <<= 7;
v |= (b & 0x7f) as usize;
if b & 0x80 != 0 {
return v;
}
}
panic!("Truncated varuint");
}
}
fn push_varuint(v: &mut Vec<u8>, mut value: usize) {
let mut buf = [0; (usize::BITS / 7 + 1) as usize];
let mut pos = 0;
while value != 0 {
buf[pos] = (value & 0x7F) as u8;
value >>= 7;
pos += 1;
}
buf[0] |= 0x80;
pos = pos.max(1);
for i in (0..pos).rev() {
v.push(buf[i]);
}
}
fn parse_varuint(buf: &[u8]) -> usize {
let mut value: usize = 0;
for b in buf {
value <<= 7;
value |= (b & 0x7F) as usize;
if b & 0x80 != 0 {
break;
}
}
value
}
|
